In recent years, liquid crystal display devices with touch panels that have a combined function of an input device have been widely used as display devices of electronic apparatuses including mobile telephones and portable game devices.
Such a touch panel has a touch panel substrate in which a conductive layer having a light transmission property or the like is laminated on a transparent substrate and a film is laminated on the outermost surface to detect an operation location of a finger or the like according to a change in capacitance, or the like.
As touch panels, various types of touch panels such as a resistive film type and a capacitive type according to differences in their structures and detection methods are known.
For example, a touch panel substrate provided with a film-like upper substrate and lower substrate having a light transmission property is known. A plurality of substantially strip-shaped upper conductive layers having a light transmission property such as indium tin oxide or the like are formed on an upper surface of the upper substrate to be arrayed in the front-rear direction. In addition, a plurality of upper electrodes formed by overlapping conductive metal foil of copper, silver, or the like on indium tin oxide or the like using vapor deposition or the like are formed in the left-right direction that is an orthogonal direction to the upper conductive layers. A plurality of substantially strip-shaped lower conductive layers having a light transmission property such as indium tin oxide or the like are formed on an upper surface of the lower substrate to be arrayed in the left-right direction that is orthogonal to the upper conductive layers. In addition, a plurality of lower electrodes that are similar to the upper electrodes of which the terminals of one side are connected to the terminals of the lower conductive layers are formed in the left-right direction that is parallel with the lower conductive layers.
Furthermore, a film-like cover substrate having a light transmission property is overlaid on the upper surface of the upper substrate and bonded to the touch panel substrate by an adhesive.
FIG. 7 is a cross-sectional diagram of a touch panel of the related art. In FIG. 7, reference symbol P represents a touch panel substrate, and reference symbol C represents a cover substrate. A light shielding film th having a non-light-transmission property is provided on an edge part E of the surface of the cover substrate C facing the touch panel substrate P positioned on the outer circumference or an outer side of a touch area (display area) T in which operations are performed.
This light shielding film th is known to be formed to a thickness of about 5 μm to 20 μm on the cover substrate C using printing or the like as disclosed in Patent Literature 1.
However, when the light shielding film th having the non-light-transmission property at the edge part E is formed on the surface of the cover substrate C facing the touch panel substrate P approximately in the thickness dimension using printing, a space is made between the cover substrate C and the touch panel P as indicated by Air in FIG. 7, and reflection occurs on the rear surface of the cover substrate C or on the surface of the touch panel substrate P, which results in problems that visibility deteriorates and output of a display means is impeded due to the deterioration in visibility.
Furthermore, if a conductor such as a metal is provided on the edge part E as disclosed in Patent Literature 1, the conductor has a different dielectric constant from the cover substrate C or the panel part P, and thus there is a possibility of a property such as a radio property deteriorating, which is not favorable.
In addition, Patent Literature 2 discloses a touch panel.